In a next-generation radio access network (new radio, NR), a downlink base station completes coarse downlink time and frequency synchronization by using a synchronization signal. The synchronization signal includes a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). User equipment (UE) may receive the primary synchronization signal and the secondary synchronization signal, to implement synchronization and obtain cell identification information. The user equipment first detects the primary synchronization signal to determine a center frequency and basic time and frequency synchronization information or parts of cell identification information, and then obtains the cell identification information by using the secondary synchronization signal. Usually, there may be a small quantity of possible different primary synchronization signals, for example, three primary synchronization signals or one primary synchronization signal. The 3rd Generation Partnership Project (3GPP) discussed generation of a primary synchronization signal by using a longest linear feedback shift register sequence. In addition, a secondary synchronization signal may also be generated based on a scrambled m-sequence or a Gold sequence. The m-sequence is short for a longest linear shift register sequence. Usually, to distinguish between the primary synchronization signal and the secondary synchronization signal, a primary synchronization signal sequence and a secondary synchronization signal sequence are different.
In a fifth-generation mobile communications technology (5G), a length of a new synchronization signal sequence may be greater than or equal to a length of a synchronization signal sequence in Long Term Evolution (LTE). An orthogonal frequency division multiplexing technology (OFDM) is used to transmit a synchronization signal. That is, a primary synchronization signal sequence is mapped onto a subcarrier in an OFDM system that is allocated to a primary synchronization signal, and a secondary synchronization signal sequence is mapped onto a subcarrier in the OFDM system that is allocated to a secondary synchronization signal.
In an existing solution, the primary synchronization signal and the secondary synchronization signal occupy one OFDM symbol, and sizes of occupied bandwidths are the same and are N, where N is an integer, for example, 127. When a network device detects a primary synchronization signal, a secondary synchronization signal in another cell or in a local cell interferes with detection of the primary synchronization signal.